fix: setup prismic image host

[Clecio013]

I was following this example and had an error to display prismic's image, it's because we need to configure the host image in next.config.js

Here's the docs about it https://nextjs.org/docs/messages/next-image-unconfigured-host

Bug

Don't have issue yet

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Documentation / Examples

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[ijjk]

Thanks for the PR!